Hello there, I had a copper IUD for 5 yrs. Never once used any other kind of birth control, and never got pregnant. Well, that I know of.... What I didn't know when I had it inserted is that a copper IUD doesn't prevent fertilization, it makes your uterus soooo unhappy that nothing can implant or stay implanted. For the first year I was really crampy off and on and my period was irregular. So you techinally could have conceived, but the chances of a embryo (or is it zygote?) implanting or sustaining a pregnancy are slim. But the really good news about the copper IUD is that the day you have it removed, you have the same chance of getting pregnant again just as if you never had it. I got pregnant the same month that we started trying after having it removed. So good luck to you. I know you weren't looking for an answer but I rarely come across anybody who's had a copper IUD. so thank you for opening the door and letting me talk!